The present invention relates to a closure device particularly usable in ski boots comprising a front quarter and a rear quarter associated with a shell, and having a pivoting lever.
Several devices are currently known for closing the quarters, generally constituted by a cable the ends whereof are associated with the sides of the front quarter; the cable is then connected to an adapted vertical lever associated with the rear quarter.
Such known devices have some disadvantages, among which a main one is that the working length of the cable is usually insufficient to also allow the complete opening of the quarters when the lever is opened, and it is therefore difficult to insert the foot in the boot.
As a partial solution to these disadvantages, a French Patent Application, no. 82 19676, dated Nov. 24, 1982, discloses a quarter closure device which comprises a strap embracing the front quarter, and an array of holes, arranged along two parallel axes on said strap.
Two cables are associated within said holes, partially wind on a longtudinal projection at the rear quarter and engage with a vertical lever.
A variated embodiment is also illustrated in which two pulleys are provided instead of said projection and the lower pulley is adjustable.
This known device, however, also has disadvantages: it is structurally complicated and bulky, because of the fixed projecting guide which occupies most of the rear quarter, and also the lay-out of the cables is excessively complicated.
A French Patent Application no. 8508207 published as No. 2582486 filed on May 31, 1985, discloses a device for tensioning a flexible element for connecting two elements and is particularly applicable for closing the quarters of a ski boot. The flexible connecting element passes into a first movable guide element which is supported by a pivoting lever, for the tensioning thereof, so as to make a first loop, then passes around a second fixed guide element and forms a second loop; the flexible connecting element and the two guide elements constitute the equivalent of a pulley.
This device has the disadvantage that most of the possible embodiments can be provided only by using straps, because the loops radius is very small.
Furthermore, the pivoting axis of the lever must be at a considerable distance from the boot surface, to keep the lever in the closed position.
It is therefore difficult to insert the lever in the boot from a styling point of view, and this lever is in any case bulky.
The use of a strap as flexible connecting element furthermore entails, in the described solutions, the tensioning of said strap during the first lever opening step: this, too, is a disadvantage, since the quarters are tightened further on the leg.
The device therefore has a structure which is not easy to operate.
U.S. Pat. No. 4,691,454 discloses a closure system for ski boots wherein a lever system is adapted to operate two cables. This lever system can take up a longer portion of cable than with respect to the traditional lever systems but this is accomplished with a very complicated and heavy structure.
Finally, it is known that in the known levers for closing the quarters in a ski boot, a rotation of approximately 180 degrees of said lever is followed by the take-up of a length of cable, which is equal to twice the distance between the pivoting axis of the lever and the connection point of the cable on said lever.
It is furthermore known that during the first part of the rotation imparted to these known levers there is no tensioning of the cables, and no work is produced in this step.